/**
 * Copyright (c) 2005-2012 springside.org.cn
 */
package com.betterjr.common.utils;

import java.io.UnsupportedEncodingException;
import java.math.BigInteger;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.security.MessageDigest;

import org.apache.commons.codec.DecoderException;
import org.apache.commons.codec.binary.Base64;
import org.apache.commons.codec.binary.Hex;
import org.apache.commons.lang3.StringEscapeUtils;

import com.betterjr.common.exception.BytterException;

/**
 * 封装各种格式的编码解码工具类. 1.Commons-Codec的 hex/base64 编码 2.自制的base62 编码
 * 3.Commons-Lang的xml/html escape 4.JDK提供的URLEncoder
 * 
 * @author calvin
 * @version 2013-01-15
 */
public class Encodes {

    private static final String DEFAULT_URL_ENCODING = "UTF-8";
    private static final char[] BASE62 = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz".toCharArray();

    /**
    * Hex编码.
    */
    public static String encodeHex(byte[] input) {
        return new String(Hex.encodeHex(input));
    }

    /**
    * Hex解码.
    */
    public static byte[] decodeHex(String input) {
        try {
            return Hex.decodeHex(input.toCharArray());
        }
        catch (final DecoderException e) {
            throw BytterException.unchecked(e);
        }
    }

    /**
    * Base64编码.
    */
    public static String encodeBase64(byte[] input) {
        return new String(Base64.encodeBase64(input));
    }

    /**
    * Base64编码.
    */
    public static String encodeBase64(String input) {
        try {
            return new String(Base64.encodeBase64(input.getBytes(DEFAULT_URL_ENCODING)));
        }
        catch (final UnsupportedEncodingException e) {
            return "";
        }
    }

    // /**
    // * Base64编码, URL安全(将Base64中的URL非法字符'+'和'/'转为'-'和'_', 见RFC3548).
    // */
    // public static String encodeUrlSafeBase64(byte[] input) {
    // return Base64.encodeBase64URLSafe(input);
    // }

    /**
    * Base64解码.
    */
    public static byte[] decodeBase64(String input) {
        return Base64.decodeBase64(input.getBytes());
    }

    /**
    * Base64解码.
    */
    public static String decodeBase64String(String input) {
        try {
            return new String(Base64.decodeBase64(input.getBytes()), DEFAULT_URL_ENCODING);
        }
        catch (final UnsupportedEncodingException e) {
            return "";
        }
    }

    /**
    * Base62编码。
    */
    public static String encodeBase62(byte[] input) {
        final char[] chars = new char[input.length];
        for (int i = 0; i < input.length; i++) {
            chars[i] = BASE62[(input[i] & 0xFF) % BASE62.length];
        }
        return new String(chars);
    }

    /**
    * Html 转码.
    */
    public static String escapeHtml(String html) {
        return StringEscapeUtils.escapeHtml4(html);
    }

    /**
    * Html 解码.
    */
    public static String unescapeHtml(String htmlEscaped) {
        return StringEscapeUtils.unescapeHtml4(htmlEscaped);
    }

    /**
    * Xml 转码.
    */
    public static String escapeXml(String xml) {
        return StringEscapeUtils.escapeXml10(xml);
    }

    /**
    * Xml 解码.
    */
    public static String unescapeXml(String xmlEscaped) {
        return StringEscapeUtils.unescapeXml(xmlEscaped);
    }

    /**
    * URL 编码, Encode默认为UTF-8.
    */
    public static String urlEncode(String part) {
        try {
            return URLEncoder.encode(part, DEFAULT_URL_ENCODING);
        }
        catch (final UnsupportedEncodingException e) {
            throw BytterException.unchecked(e);
        }
    }

    /**
    * URL 解码, Encode默认为UTF-8.
    */
    public static String urlDecode(String part) {

        try {
            return URLDecoder.decode(part, DEFAULT_URL_ENCODING);
        }
        catch (final UnsupportedEncodingException e) {
            throw BytterException.unchecked(e);
        }
    }

    /**
     * 对字符串md5加密
     *
     * @param str
     *            传入要加密的字符串
     * @return MD5加密后的字符串
     */
    public static String getMD5(String str) {
        try {
            // 生成一个MD5加密计算摘要
            final MessageDigest md = MessageDigest.getInstance("MD5");
            // 计算md5函数
            md.update(str.getBytes());
            // digest()最后确定返回md5 hash值，返回值为8为字符串。因为md5 hash值是16位的hex值，实际上就是8位的字符
            // BigInteger函数则将8位的字符串转换成16位hex值，用字符串来表示；得到字符串形式的hash值
            return new BigInteger(1, md.digest()).toString(16);
        }
        catch (final Exception e) {
            e.printStackTrace();
            return null;
        }
    }
}
